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Technical Forums => Twin Cam => Topic started by: Retro on July 23, 2019, 06:11:12 AM

Title: Andrews 37 S&S 98 big bore not compatible?
Post by: Retro on July 23, 2019, 06:11:12 AM
Hi guys!

Have an S&S big bore kit on order and today this guy says that they're not compatible with my Andrews 37 cams. What do you think about that? Is he full of it or does the 37's have too high of a lift? Confused.

Thanks!
Title: Re: Andrews 37 S&S 98 big bore not compatible?
Post by: rigidthumper on July 23, 2019, 07:03:13 AM
Their concern may be excessive compression. Andrews recommends 9.0-9.5 compression for the TW37b's. I have run them up to 9.8 with no issues. The old TW37s had a 42° close, and would tolerate a little more compression.  If the kit has flat top pistons, then compression should be well within the range of any of the 37s.
Title: Re: Andrews 37 S&S 98 big bore not compatible?
Post by: Retro on July 23, 2019, 07:39:08 AM
Thanks for your answer. The pistons do have a 10cc pop-up. Should I worry about that? The comp is supposed to be 10:3.
Title: Re: Andrews 37 S&S 98 big bore not compatible?
Post by: rigidthumper on July 23, 2019, 08:12:11 AM
Stock 99-06 heads typically have 83 cc chambers. A 10 cc dome on a 98" piston, .040" head gasket, with 83cc chambers will make it closer to 10.85:1 CR. 10.8 is great for a SE251 or a Woods 8, but too high for a TW37.
Add compression releases, whatever you decide to do.
Title: Re: Andrews 37 S&S 98 big bore not compatible?
Post by: Retro on July 25, 2019, 12:46:47 AM
I have decided to go with  the S&S 585 easy start cams. Should be fine.
Title: Re: Andrews 37 S&S 98 big bore not compatible?
Post by: rigidthumper on July 25, 2019, 07:12:10 AM
 :up:
Title: Re: Andrews 37 S&S 98 big bore not compatible?
Post by: FXDBI on July 25, 2019, 09:12:05 AM
Quote from: Retro on July 25, 2019, 12:46:47 AM
I have decided to go with  the S&S 585 easy start cams. Should be fine.

It will like the compression your set at.   Bob